Work-holder mechanism for buttonhole-sewing machines



E. B ALLEN. WORK HOLDER MEBHANISM FOR BUTTONHOLE SEWING MACHINES. APPLICATION FILED JULY 16, 1917. 1,331,176. Patented Feb. 17,1920.

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f/ZL I ATTW E. B. ALLEN.

WORK HOLDER MECHANISM FOR BUTTONHOLE SEWING MACHINES.

APPLICATION FILED JULY I6, 1917.

o, N U m m b A W m m A m a 6 P 0 ,4 w WW I x\ EXQW 6 7 1 v 1 a W 3 m ITED STATES PATENT OFFICE- EIDWARD B. ALLEN, F BRIDGEPORT, CONNECTICUT, ASSIGNOR TO THE SINGER MANUFACTURING COMPANY, A CORPORATION OF NEVI JERSEY.

WORK-HOLDER MECI-EANZSIE Specification of Letters Patent.

R BUTTONHOLE-SEWING MACHINES.

Patented Feb. 17, 1920.

To all whom it may concern Be it known that I, EDWARD l3. ALLEN, a citizen of the United States, residing at Bridgeport, in the coiurty of Fair-field and State of Connecticut, have invented certain new and useful Improvements in Fort; Holder Mechanisms for Buttonhole-Sewing Machines, of which the following is a speci fioation, reference being had therein to the accompanying drawings.

This invention relates to work-holder mechanism for buttonhole sewing machines and particularly to machines in which the work-holder comprises work-clamps which are automatically closed upon the work and then moved apart or spread to widen the buttonhole slit after it is cut and preparetory to the stitching operation.

In the case of machines adapted to operate upon leather and having stitch-forming mechanism including a lower curved needle, it is desirable in starting the operation of stitching that the extreme end-portion of the huttonhole slit opposite the eye be widened or spread sufficiently to provide room for the free passage of the lower or overedge needle in its initial ascent, to prevent springing or deflecting of the needle which, in turn, would cause deflection the upper or depth-stitch needle and consequent misplaced stitching.

It has been found that the various workclamps heretofore known are imperfect operation upon leather for the reason that the material adjacent the end of the slit offers great resistance to the stretching or spreading operation and, as a result, the usual serrations formed on the work-clamping elements sink into the leather more r less and do not spread the extreme endportion of the slit as 11111011 as the side-portions thereof where little resistance-is (if-- great variety of leathers in which the buttonholes are to be stitched and on account of the difiiculty of holding any particular grade of material securely so that, when clamped, cut and spread, the edges of the slit will be held in parallel and properly spaced relation throughout their extent.

The present invention has for an object to provide work-holder mechanism by means of which the material at either end of the location where the buttonhole is to be stitched may be spread or stretched to any desired extent.

Another object of the invention is to provide a work-holder mechanism adapted for use in connection with various elastic and inelastic materials and, particularly, for operation upon various grades and qualities of resistant material, such as leather, and which may be caused to spread the buttonhole slit evenly and to the desired extent throughout its entire length.

In the preferred embodiment of the invention, the work-holder comprises a pair of clamping plates mounted for bodily and turning movements toward and from each other upon a traveling support and sustaining upper clamping levers carrying serrated clamping feet adapted to cooperate with serrated portions of said plates in gripping the work. In the present instance, independently adjustable means are provided at the opposite ends of the plates for effecting the separation thereof to secure the desired relative stretching actions at the 0pposite ends of the buttonhole slit.

The invention will be understood by reference to the accompanying drawings, in which Figure l is a plan view of the workholder with the rearward end-portions of the clamping levers broken away and their supporting brackets removed. Fig. 2 is a side elevation of the work-holder. Fig. 3 is a cross-section on the line 33 of Fig. 1. Fig. 1h is a perspective view from below showing the work-clamping plates and their retaining elements. Fig. 5 is a perspective view from below showing the cross slideplate or carrier for the clamping plates. 6 is a perspective view showing the de vices which act. to spread the opposite ends of the clamp-plates. Fig. 7 is a detail of an adjusting device. Fig. 8 is a side-elevation of the clamp-unspreading cam-block and parts closely associated therewith; Fig. 9 is a top plan View of the clamp-unspreading cam-block and Fig. 10 is a side-elevation of the same opposite to the showing in Fig. 8.

While the present improvement is useful in machines which cut the material after it is spread and stitched, it is particularly useful in machines which employ means for cutting the buttonhole before stitching and which are provided with stitch-forming mechanism of the type represented in my Patent No. 1,162,207, of November 30, 1915;

the present work-holder being a development of that disclosed in my pending appli cation Serial No. 41,884, filed July 26, 1915.

The invention in its preferred embodiment comprises the well-known longitudinally traveling slide-plate 1 having inwardly directed flanges 1 adapted to slide along the undercut guideways in the top of the machine bed in the usual manner disclosed, for example, in my Patent No. 1,039,241, of September 24, 1912. The slide-plate 1, at its forward end, sustains the usual cross-rod 2 which enters the downwardly projecting apertured lugs 3 formed on the cross slideplate or carrier 4. Longitudinal and lateral traveling movements may be imparted to the carrier 4 by usual or suitable connections with the feed-wheel 5 such, for example, as represented in my pending application Serial No. 17,595, filed March 29, 1915. Secured to the upper side of the front end-portion of the carrier 4 by screws 6 is the transversely extending retainer plate 7 the straight rearward edge of which is undercut to form an overhanging flange 9 which is adapted to fit over he flanges 10 at the curved front ends of the clamp-plates 11 the flanged and curved rearward ends of which are held down upon the carrier 4 by means of the overhanging flanges 12 of suitable longitudinally slotted retainers 13 which are adjustably secured to'the slideplate 1 by means of screws 14. The opposed flanges 9 and 12 define a transverse slideway along which the clamprplates- 11 are adapted to partake of bodily lateral movements and also, by virtue of their curved ends, of limited angular or turning movements.

The work is clamped against the serrated portions ll of the clamp-plates 11 by means i of the usual serrated clamping feet 15 pivotally secured to the forward ends of the clamp-arms 16 which are fulcrumed at their rearward ends within brackets 17 secured to the clamp-plates 11 in a manner well known as fullv A disclosed in my said Patent No. 1,162,207. It may be here explained that the opposed serrated or work-engaging portions of the clamping'plates 11 and feet 15 grip the material at opposite sides of a buttonhole slit and maybe considered as comprising distinct operative work-engaging portions 15 and 15"; the former for gripping the material adjacent the front end of the buttonhole slit, 2'. 6., in the present instance, the end opposite the eye, and the latter for gripping the material adjacent the rear or in the present instance the eyelet end of the buttonhole slit.

The forward ends of the clamping plates 11 are preferably spring-pressed toward each other by means of the levers 18 pivotally mounted in the recesses 19 in the under side of the retainer-plate 7 and having pointed rearward extremities engaging the shoulders 20 afforded by suitable notches in the flanges 10. The forward extremities of the levers 18 are curved downwardly to form finger-pieces and are urged outwardly to force the front ends of the clamp-plates inwardly by means of tension springs 21. A stop 22 secured to and projecting rearwardly from the retainer-plate 7 serves to limit the mutual approach of the front ends of said clamp-plates under the influence of the springs 21.

The rearward ends of the clamp-plates are preferably urged toward each other by means of the springs 23 mounted thereon and formed with rearwardly projecting ends which bear outwardly against suitable abutments 28 fixed to the longitudinal slideplate 1. Steps 24 fixed to the cross slideplate or carrier 4 serve to limit the mutual approach of the rearward ends of the clampplates under the influence of the springs 23. The rear ends of the clamp-plates 11 are notched to afford stop-shoulders 24 adapted to encounter the stops 24.

The clamp-spreading mechanism to be described is not only adapted to impart bodily lateral motion to the clamp-plates 11 in opposition to the springs 21 and 23 but also a turning or angularmotion so that, when. the clamp is spread, the opposite ends of the clamp-plates may, if desired, be separated unequal distances to secure unequal stretching actions at the opposite ends of a button hole slit. Moreover the mechanism is pro vided with such adjusting means that the material at either end of a buttonhole slit, or at either end of the location where the buttonhole is to be formed, may be subjected to any desired stretching action.

Adjustably secured by means of screws 25 to the upper sides of the clamp-plates 11 near their rearward ends are the transversely extending slotted plates 26, the outer downturned and bifurcated ends of which overhang the outer edges of the clamp plates 11 and embrace the grooved shanks 27 of the adjusting screws 28 tapped into v the outer edges of said clamp-plates. Fixed to the inner ends of the adjustable plates v26 are the downwardly extending stud-pins 29 'which project through the elongated slots 30 in the clamp-plates 11 and are adapted to be engaged and forced outwardly by the inclined outer cam-edges of the cam-blocks 31 fixed to the rearward ends of the U- shaped slide-plate 32 let into the upper surface of the cross slide-plate 4 and free to partake of longitudinal movements.

The cross-member 32 of the U-shaped slide-plate 32 is formed at its inner edge with a circular recess within which is fitted the circular end of a link 33 whose opposite circular end is fitted within a corresponding recess in a crank-arm 34 fixed to the upper end of a rocking pin 35 sustained by the cross slide-plate 4. Thus, the rocking of the pin 35 through the described connections causes the to-and-fro movement of the U-shaped slide-plate 32 and the consequent engagement of the cam-blocks 31 with the studpins 29 to effect the separation and approach of the rear ends of the clamp-plates 11 in opposition to and under the influence of the springs 23.

To spread the front ends of the clampplates the rocking pin 35 is provided with a concentric head 36 having oppositely disposed fiattened sides affording dian'ietrically opposed thrust shoulders or corners 37 which are adapted to engage the inner ends of and separate the plates 38 let into the under sides of the clamp-plates 11 near the front ends of the latter. The plates 38 are adjustable and may be secured in the desired position of adjustment by means of screws 39 whose shanks pass through elongated slots 40 in the clamp-plates and are threaded into said adjustable plates 38.

The mechanism for rocking the pin 35 to spread and unspread the work-clamping elements above described is similar in general construction to that shown and de scribed in my Patent No. 1,240,642 granted Sept. 18, 1917. The pin 35, has fixed upon its lower end the hub 41 of the lateral arm 42 attached to one end of the spring 43 whose opposite end is attached to a stud 44 upon the cross slide-plate 4. The hub 41 is provided also with the oppositely extending rigid arms 45 and 46 disposed at sub stantially right angles to the arm 42.

The outer extremity of the arm 45 lies within the range of movement of the reciprocating cam-block 47 adjustably secured to the carrier 47 by a screw 47" which passes through a slot 47 in the shank of the cam-block 47. The carrier 47 is pivotally mounted by means of the stud-screw 48 on the head 49 of a rack-bar 50 meshing with the pinion 51 which is mounted upon the fixed stud 52 and meshes, in turn, with a series of rack-teeth 53 upon the adjacent edge of the travelingfulcrum-block 54 of the usual slit-cutting mechanism. The cam block 47 has its upper side formed at the forward extremity with a bevel 47*, and a lateral extension 55' of said cam -block has an abrupt shoulder 55' adapted for engagement with the rearward edge of the arm 45, the cam-block being maintained yieldingly within the plane of movement of the arm 45 by means of the spring 56 whose shank is secured to the head 49 of the rackbar 50 by a screw 56.

Pivoted upon the stud-screw 57 secured to the under face of the cross slide-plate 4 is a plural-armed latch-lever comprising a latch-arm 58 notched at its outer end to form a detaining shoulder for the arm 46, a second angularly arranged arm 59 having a lateral finger 60 whose extremity is beveled at 61 for engagement with the beveled upper face of the cam-block 47, a third arm 62 projecting within the range of movement of the end of the bellcrank-lever 63 pivoted to the machine frame, and a fourth arm 64 having connected therewith one end of a spring 65 whose other end is attached to a stud 66 depending from the cross slideplate 4. In the usual advance of the traveling fulcrumblock 54 of the cutting device at the beginning of buttonhole-producing cycle the rack-bar 5O recedes from advance position and the cam-block 47 is depressed by engagement of the slightly rounded corner 55 of the extension 55 with the beveled face of the arm 45; and in the retraction of the cutting device after a cutting operation,

the rack-bar 50 advances and effects the engagement of the abrupt shoulders on the parts 45 and 55, as shown in Fig. 5, thereby turning the pin 35 and through its crank and link connection with the slide-plate 32 effecting the engagement of the cam-blocks 31 with their respective followers 29 to spread the rearward ends of the clamp plates while the thrust-shoulders 37 formed on the head 36 of the pin 35 engage the follower-plates 38 and spread the forward ends of the clamps. The extremity of the arm 46 having previously rested against the adjacent edge of the latch-lever arm 58, is moved along the same in the turning of the pin 35 until it comes into register with the notch of the latch-arm, when the latter un der the action of the spring 65 snaps into locking engagement therewith to hold the clamps in spread position during the succeeding stitching operation.

In the present instance, when the bellcrank-lever 63 is rocked by means of the projection 68 on the usual feed-cam 5 at the end of a buttonhole-producing cycle, its forward extremity engages the arm 62 of the latch-lever and turns the latter to disengage the latcl1arm 58 from the arm 46. At the same time the wedge-shaped extremity 61 of the finger 6O strikes the inclined face 47 of the camblock 47 and wedges the latter downwardly to permit the arm 45 to assume nor mal unspread position with the arm 46 drawn into contact with the stop-pin 67 by the action ofthe spring 43; the return more ment of the rocking pin 35 thus causing the parts to assume unspread position, as shown in Fig. 1, wherein the clamp-plates 11 are held against the stops 22 and 24: by means of the springs 21 and 23. By adjusting the plates 38 closer to or farther from the head 36 an increased or decreased sareadm ac -t1on at the forward ends of the clamplower cooperative work-engaging portions 1 5 be integrally connected with the respective portions 15 as in the embodiment illustrated. The important consideration is the provision of means whereby the material adjacent either end of the buttonhole may be spread to any desired degree before stitching and either before or after cutting.

It is evident that the form and arrangement of the various parts are susceptible of very material modification within the scope of the invention; the foregoing descriptive matter being merely illustrative of the novel principles involved, and that many modifications of design, detail, arrangen'ient and combinations of parts will no doubt readily suggest themselves to those skilled in the art.

Having thus set forth the nature of the invention, what I claim herein is .1. A work-holder for buttonhole sewing machines comprising a carrier, clamping elements mounted on said carrier for angular and bodily lateral spreading movements, actuating means for imparting said spreading movements to said elements, and adjusting means whereby a variation of said movements may be secured to effect any desired relative spreading action at the opposite ends of a buttonhole slit.

2. A work-holder for buttonhole sewing machines comprising clamping devices for gripping the material at opposite sides of a buttonhole slit, said clamping devices being mounted to partake of spreading movements of translation and rotation, and actuating means for imparting the desired components of spreading motion to said devices.

. 3; A work-holder for buttonhole sewing machines comprising work-clamping devices having operative work-engaging portions adapted to clamp the work at opposite sides of an eyelet-end buttonhole slit, and actuate ing means for spreading the work-engaging portions adjacent the end of the buttonhole slit where the stitching is to begin a greater distance than the work-engaging portions 7 adjacent the opposite end of said slit.

4. A work-holder for eyelet-end buttonhole sewing machines comprising work clamping devices having operative work-engaging portions adapted to clamp the work at opposite sides of an eyeletend buttonhole slit, and actuating means for spreading the turning movements to said devices in opposite directions to spread the operative work-engaging portions thereof adjacent the end of the slit opposite the eye a greater distance than the operative portions adjacent the eye of said slit.

6. A work-holder for buttonhole sewing machines comprising work-clamping devices having operative work-engaging portions adapted to clamp the work at oppositesides of a buttonhole slit, and adjustable actuating means for spreading the work-engaging portions adjacent either end of the buttonhole slit any desired proportionally greater distance than the work-engaging portions adjacent the oppositeend of said slit.

7. A work-holder for buttonhole sewing machines comprising, a carrier, clamp-plates mounted thereon for spreading movements relatively thereto, cooperative clamping elements carried'by said'plates for clamping the work at opposite sides of a buttonhole slit and actuating means for spreading said clamping plates, said actuating means comprising connections for imparting differential spreading movements to each of said plates at two spaced points.

8. A work-holder for buttonhole sewing machines comprising, work-clamps having operative work-engaging portions adapted to clamp the work at opposite sides of a but tonhole stitching location and a plurality of differentially moving clamp-spreading means acting uponsaid clamps at spaced points to spread the work prior to stitching.

9. A V work-holder for buttonhole sewing machines comprising laterally separable work-clamps having work-engaging portions for clamping and spreading therwork and a plurality of independently adjustable means forspreading different portions of said clamps different distances to suit the requirements of the work at hand.

10. A work-holder for buttonhole sewing machines comprising, work-clamps having operative work-engaging portions adapted to clamp the work at opposite sides of a buttonhole slit and a plurality of independently adjustable spreading devices acting upon each of said clamps at spaced points to spread the opposite ends of a buttonhole slit distances bearing any desired ratio to one another Within certain limits.

11. A Work-holder for buttonhole sewing machines comprising Workclamping elements having operative Work-engaging portions adapted to clamp the Work at opposite sides of a buttonhole slit adjacent the ends, and adjustable actuating means for spreading said operative Work-engaging portions of said clamps adjacent the ends of the buttonhole slit distances bearing any desired ratio to one another Within certain limits.

12. A Work-holder for buttonhole sewing machines comprising, a carrier having a slideway, bodily movable clamp-plates fitted to said slideway, clamping arms carried by said clamp-plates, a plurality of clampspreading cams spaced transversely of said slideway, and a plurality of cam-followers mounted on each of said clamp-plates and adapted to be acted upon by said cams.

13. A Work-holder for buttonhole sewing machines comprising a carrier, Work-clamping elements mounted on said carrier for angular and bodily lateral spreading movements and actuating means for imparting said spreading movements to said elements.

14. A Work-holder for buttonhole sewing nachines comprising, Work-clamping devices having operative Work-engaging portions adapted to clamp the Work at opposite sides of a buttonhole slit, and a plurality of difierentially acting spreading means for spreading different aortions of said workclamping devices di erent distances.

15. A Work-holder for buttonhole sewing machines comprising, Work-clamping devices having operative Work-engaging portions adapted to clamp the Work at opposite sides of a buttonhole slit, and a plurality of spreading means acting upon each of said clamping devices at spaced points to spread different portions of said clamping devices difierent distances.

In testimony whereof, I have signed my named to this specification.

EDWARD B. ALLEN. 

